This invention relates to a device arranged at the outlet of a draw frame. The draw frame has, immediately downstream of the output rolls of the draw unit, a sliver guide for the outputted blended sliver (composed of a plurality of drawn slivers). The sliver guide is arranged upstream of a sliver trumpet which, in turn, is associated with after-connected withdrawing rolls. The sliver guide has a conical or concave surface provided with a passage and is constructed such that air may be removed therefrom during operation.
In a known device, as disclosed in German Offenlegungsschrift (application published without examination) 26 23 400, the sliver guide has a slide surface of concave configuration, and along its upper and lower edges recesses are provided for allowing air to escape. A symmetrically oriented guide channel is provided in the slide surface. The sliver which is discharged by the output rolls of the draw unit and which has a width of, for example, 100 mm, engages directly the slide face and is guided by its concave shape into the inlet opening of the guide channel. When the output speed of the draw frame is increased, for example, to 800 m/min and above (for example, to 1000 m/min), the air which flows back onto the sliver from the narrow passage of the sliver guide constitutes a source of disturbance. The effect of the backflow of air, because of the significant compression of the sliver, increases more than proportionately to the speed increase. The environmental air is entrained by the sliver into the passage at an air flow rate which increases proportionately to the running speed of the sliver. In case the sliver is densified from a large width as it is forced to pass through the passage, then at speeds above 800 m/min the backflow speed of air is excessively high. It is a further disadvantage of known arrangements that the significant compression of the sliver leads to excessive friction between the wall face of the inlet and outlet opening of the sliver guide.